Due to the increasing demand for oil globally, there is a serious necessity to meet rising energy demands. Maximum percentage of oil extracted from a reservoir ranges from 30-60%, when companies utilize enhanced oil recovery techniques. Consequentially, a large subset of residual oil remains in the reservoir. Exploration for new wells is a lengthy and intensive process because of the work required, which includes locating potential reservoirs, mapping the reservoir, and characterizing oil and rock properties in the reservoir. Utilizing existing oil reservoirs to meet the demand for oil can reduce the need for more exploration. Locating residual oil in trapped pores will help extend production of current reservoirs. New research on particles suspended in a water solution has been conducted to develop particles as sensors to the oil-water interface. Due to the oil trapped in small pores, delineating the precise interfacial behavior between particles advecting through the media and the fluid phases is key. Microfluidic devices can enable pore scale measurements and provide qualitive confirmation of the interfacial processes occurring. Fabrication of microfluidic devices has been greatly explored in using photolithography and etching techniques to make silicon molds. In chapter 2, Hot Embossing, Pressing, and Bonding techniques were used in conjunction with a silicon mold to fabricate microfluidic devices with 10-20 um features. With the unique requirement to trap oil in the device, polypropylene was used as the device material due to is chemical resistance against oil and high hydrophobicity. The translucency of polypropylene devices enabled qualitative confirmation of a sustained oil-water interface with oil trapped in pockets inside the device. In chapter 3, quantification methods and analysis were developed for the device using hydrophilic nano- and microparticles. This chapter presents work both on tracking the oil-water interface and creating the industry standard breakthrough curves. Breakthrough curves show several factors about multiphase flow including breakthrough and saturation time as well as pore-scale particle velocity. In chapter 4, hydrophobic particles in oil were flowed into a device primed with oil. The particle’s advection and diffusion through the channel was compared to the 2-D Convection-Diffusion equation via simulations. The simulations enabled calculation of the effective diffusivity and Peclet number. Additionally, a key parameter to sensing oil can be extracted from the experiments: relating a volumetric quantity of oil to a particle. Lastly, chapter 5 presents the cumulation of the work from sustaining an oil-water interface, tracking particles, and flowing hydrophobic particles. This chapter’s work demonstrates the ability to test sensor particles’ interaction with the oil-water interface. Particles were first shown to partition to the interface and across the interface on a glass slide. Next with the added complexity of advection, particles were shown to partition to the interface in the microfluidic device. Additionally, the rate of partitioning could be determined from image analysis. Overall, this work presents a microfluidic device that enables particle tracking and analysis of particles sensing the oil-water interface. Key features of the device are analyzing particles advection and interactions with the interface. Diffusion of particles can also be tracked and the sensed amount of volume of oil per particle can be extracted.